Home Perl Programming Page 2 - Perl Lists: A Final Look at List::Util

# Min(List)...Your Guide to Minimalism - Perl

Welcome to the sixth part of our series on Perl Lists. Here we will cover the remaining four List::Util subroutines: min(list), minstr(list), shuffle(list), and sum(list). We'll learn how to manipulate lists using these subroutine in various intended and unintended ways.

By: James Payne
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April 21, 2008

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Min(List) is very similar to max(List) in its usage. The only difference is that it returns the minimum numeric value in a list. Here we have it in code:

#!/usr/bin/perl

use List::Util qw(min);

@Nums=(1,900,50,22);

\$Low=min(@Nums);

print \$Low;

Here, we create a list named '@Nums', in which we store several numeric values. Next, we use min() to scan the list and find the lowest value, and store it in the \$Low variable. Finally, we print the value out, resulting in:

1

As with our other subroutines, we can use min() in conjunction with operators, statements, and the like. Here it is with an if...else statement:

#!/usr/bin/perl

use List::Util qw(min);

@Nums=(1,900,50,22);

\$Low=min(@Nums);

if(\$Low > 2) {print "The number \$Low is greater than 2!"}

else {print "The value \$Low is less than 2!"};

Again, we call our subroutine, then create the @Nums list, filling it with values. We then use min() to parse out the lowest value and store it in \$Low. Lastly, we create an if...else statement that says if the value of \$Low is greater than two, print out a statement. If the value is less than two, print out another statement. You will note of course that if the value were two, nothing would have happened. Here is the result:

The value 1 is less than 2!

We can perform some mathematics on our subroutine as well:

#!/usr/bin/perl

use List::Util qw(min);

@Nums=(1,900,50,22);

\$Low=min(@Nums) + 1 * 25 +6 /9 -2;

print \$Low;

Here we take the value of \$Low and beat it to death with a bunch of math that I randomly selected, yet which oddly enough put us almost back at the number 25:

24.66666666666667

Give or take a six...

Finally, here is how we can compare the lowest values from two separate lists and have something occur from the result:

#!/usr/bin/perl

use List::Util qw(min);

@Nums=(1,900,50,22);

@Nums2=(90..898);

\$Low=min(@Nums);

\$Low2=min(@Nums2);

if(\$Low > \$Low2) {print "\$Low is greater than \$Low2"}

else {print "\$Low is less than \$Low2"};

print "\n" .\$Low . "\n";

print \$Low2;

Here, this code creates two lists, @Nums and @Nums2. It assigns the first list some numeric values, and then uses a sequential operator to add the values 90-898 to @Nums2. Next, it uses min() to extract the lowest numeric value from @Nums and assign it to \$Low. It then uses min() again to assign the lowest numeric value in @Nums2 to the variable \$Low2. Finally, it runs an if...else statement that states if \$Low is greater than \$Low2, print something. Otherwise it will print something else. Note that if \$Low and \$Low2 are equal, nothing will happen.

Here is the result:

1 is less than 90

1

90

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